Lithium cell battery

ABSTRACT

The invention concerns an electrochemical lithium cell battery ( 10; 12; 14 ) comprising at least one positive electrode ( 5, 6 ), at least one liquid electrolyte including at least one lithium salt, and at least one negative electrode ( 1, 2 ) Said cell battery ( 10; 12; 14 ) is characterized in that it comprises at least one layer ( 3, 13 ) of a gelled separator (SG) comprising at least one polymer (PG), capable of being gelled by the liquid electrolyte, which is at least partly gelled by the liquid electrolyte, in contact with the negative electrode ( 1, 2 ), and in that it comprises at least a layer ( 4 ) of a plasticized separator (SP), including at least one polymer (PP) capable of being plasticized by the liquid electrolyte, at least partly in contact with the separator layer (SG). The invention is particularly applicable to hybrid and/or electric vehicles or portable appliances.

The invention relates to a lithium electrochemical cell batterycomprising at least one positive electrode (or cathode), at least oneliquid electrolyte comprising at least one lithium salt, and at leastone negative electrode (or anode). The invention also relates to theprocess for manufacturing such a battery and to the use thereof.

The extraordinary growth of the market for portable electronic equipmenthas generated, upstream, greater and greater competitiveness in thefield of rechargeable batteries or cells. Apart from mobile telephones,which have undergone extremely rapid development, the sales of portablecomputers, growing at 20% per year, entail new requirements as regardsthe performance of their power supplies. To this should also be addedthe expansion of the market for camcorders, digital cameras, portable CDplayers, wireless devices and numerous toys that more and more oftenrequire rechargeable batteries. Finally, it is probable that the 21stcentury will experience a considerable growth in electric vehicles, theemergence of which will result from the increasingly strictinternational regulations as regards toxic emissions by internalcombustion engines.

Although the battery market is presently a very attractive one, it ishowever important to make the right choice so as to be able to positionourselves for the new generation of electronic devices. In fact, it isthe progress made in electronics that dictates the specification fortomorrow's batteries. Added to the demand for more self-sufficientbatteries has, in recent years, owing to miniaturization, the desire tohave thinner and more flexible batteries. Dry polymer technology andLi-ion polymer technology may provide this flexibility. However, thefirst technology can operate only at temperatures above 60° C. andtherefore is inappropriate for portable applications. As regard thesecond technology, this is currently penetrating the portable market atthe expense, at the very least, of a loss of energy associated with theuse of carbon rather than lithium.

Lithium ion batteries use gelled high-strength membranes based onfluoropolymers, for example PVDF (polyvinylidene fluoride), which arehowever, incompatible with Li metal (dimerization reaction at theinterface). However, in addition to dendrite problems, othertechnological barriers regarding the compatibility of the polymers withLi metal remain to be raised. Specifically, dry polymer technology usesPEO (polyethylene oxide) and the gelling of this polymer, althoughpossible, results in a membrane that adheres well to Li but is of lowmechanical strength and consequently not easy to manufacture. Toalleviate these difficulties, it has been envisaged to blend togethertwo polymers, PEO and PVDF-HFP ((polyvinylidenefluoride)-co-(hexafluoropropylene)) so as to combine adhesion andmechanical strength properties. Thus, patent U.S. Pat. No. 6,165,645describes a gelled electrolyte for a lithium polymer battery, whichcomprises a polymer alloy and an organic electrolyte solution. Such analloy comprises a polymer that is difficult to dissolve in theelectrolyte solution, for example PVDF, and another polymer that issoluble in said solution, for example PEO. However, the battery usingthe technology as described in patent U.S. Pat. No. 6,165,645 suffersfrom cyclability problems associated with the formation of lithiumdendrites.

The inventors have found that, thanks to the battery according to theinvention, it is possible to optimize the use of a layer of plasticizedseparator, called PS, comprising at least one plasticizable polymer,called PP, slightly solvated by the liquid electrolyte, and of a layerof a gelled separator, called GS, comprising at least one gellablepolymer, called GP, which is predominantly gelled by the liquidelectrolyte.

According to the invention, the term “plasticizable polymer” isunderstood to mean a polymer which can be plasticized by contacting itwith the liquid electrolyte, that is to say it has a low affinity forthe liquid electrolyte. According to the invention, the term“plasticized separator layer” is understood to mean a layer of aseparator comprising predominantly at least one plasticized polymer.Such a layer is generally such that the mechanical strength of the layerof plasticizable polymer is maintained after being contacted with theliquid electrolyte, that is to say after the layer of plasticizedpolymer has been formed.

According to the invention, the term “gellable polymer” is understood tomean a polymer which can be gelled by contacting it with the liquidelectrolyte, that is to say which has a high affinity for the liquidelectrolyte. According to the invention, the term “layer of gelledseparator” is understood to mean a layer of a separator comprisingpredominantly at least one gelled polymer. Such a layer is in generalsuch that the mechanical strength of the layer of gellable polymer islost after coming into contact with the liquid electrolyte, that is tosay after the gel, namely the gelled polymer, has been formed.

The battery according to the invention is a lithium electrochemical cellbattery comprising at least one positive electrode (or cathode), atleast one liquid electrolyte comprising at least one lithium salt, andat least one negative electrode (or anode), said battery beingcharacterized in that it comprises at least one layer of a gelledseparator GS comprising at least one polymer GP, able to be gelled bythe liquid electrolyte, which is at least partly, preferably almostcompletely gelled by the liquid electrolyte, in contact with thenegative electrode, and in that it includes at least one layer of aplasticized separator PS comprising at least one polymer PP, able to beplasticized by the liquid electrolyte, which is at least partly,preferably almost completely, plasticized by the liquid electrolyte andat least partly, preferably almost completely, in contact with the layerof separator GS.

The battery according to the invention thus comprises at least onealternation of a positive electrode, a separator and a negativeelectrode, or cell. According to the invention, the battery may compriseseveral of these alternations or cells.

Advantageously, the contact between the negative electrode and theseparator GS layer ensures adhesion, thanks to the physical propertiesof the “glue” which the polymer GP gelled by the liquid electrolyteforms, and also ensures a high-quality interface. In addition, thepresence of the polymer PP ensures mechanical strength of the separatorPS. According to the invention, the term “separator” is understood tomean a physical means for separating the two electrodes, that is to saya physical means that prevents any contact between the negativeelectrode and the positive electrode, while still allowing the ionicspecies necessary for the operation of the battery to pass through it.

According to one embodiment of the invention, the separator PS layer isat least partly, preferably almost completely, in contact with thepositive electrode. In such a case, the separator is referred to as abilayer separator. Thus, in this case, said battery preferablycomprises, from the positive electrode to the negative electrode, adouble layer consisting of a separator PS layer and a Separator GSlayer.

According to another embodiment of the invention, battery comprises, inaddition, another separator GS layer, called GS_(a), at least partly,and preferably almost completely, between the positive electrode and theseparator PS layer. To simplify matters, when reference is made in therest of the text to the properties or the nature of the Separator GSlayer, the same also applies of course to the separator GS_(a) layer. Insuch a case, the separator is referred to as a three-layer separator.Thus, in this case, said battery preferably comprises, from the positiveelectrode to the negative electrode, a triple layer consisting of aGS_(a) separator layer, a separator PS layer and a separator GS layer.

The polymer PP is chosen from the group formed by polyvinylidenefluoride PVDF, polystyrene PS, polyvinyl chloride PVC, polycarbonate PC,ethylene-propylene-diene monomer EPDM, and derivatives thereof. The term“derivatives” is understood to mean any crosslinked polymer or copolymerobtained from one of these polymers. Preferably, the polymer PP ischosen from a group formed by polyvinylidene fluoride PVDF and(polyvinylidene fluoride)-co-(hexafluoropropylene) PVDF-HFP copolymersgenerally comprising from 0 (exclusive) to 30 mol %, preferably from 4to 12 mol %, of HFP. Even more preferably, the polymer PP is PVDF-HFPcopolymer generally comprising from 0 (exclusive) to 30 mol %,preferably from 4 to 12 mol %.

The polymer GP is generally chosen from the group formed by polymethylmethacrylate PMMA, polyethylene oxide PEO and polyacrylonitrile PAN, andderivatives thereof such as, for example, crosslinked polyethylene oxidecopolymers generally comprising at least one unit chosen from the groupformed by epichlorhydrin units, propylene oxide units and allyl glycidylether units. Preferably, the polymer GP is PEO.

The positive electrode preferably comprises carbon, active material,polymer PP and optionally at least one plasticizer. The term“plasticizer” is understood to mean an organic liquid or an oligomerhaving a low affinity for a polymer PP. Such a plasticizer thus makes itpossible to create, within the polymer PP, pores that the plasticizerhad occupied. Preferably, such pores may be freed by passing thematerial through a bath of a nonsolvent for the polymer PP, or by anyother method known to those skilled in the art for extractingplasticizer without modifying the structure of the polymer PP.Advantageously, during the operation of the lithium battery, such poresare occupied by liquid electrolyte, which participates in theelectro-chemical reactions at the positive electrode.

More generally, the positive electrode may comprise at least onetransition metal oxide (a transition metal being an element of one ofthe groups of the Periodic Table of the Elements) capable of reversiblyinserting and extracting lithium, for example an oxide chosen from thegroup formed by LiCoO₂, LiNiO₂, LiMn₂O₄, LiV₃O₈, V₂O₅, V₆O₁₃, LiFePO₄and Li_(x)MnO₂ (0<x<0.5). In general, the positive electrode alsoincludes a current collector, for example made of aluminum.

The negative electrode is preferably based on lithium metal, that is tosay it mainly comprises lithium metal. However, more generally, thenegative electrode may comprise metallic lithium, a lithium alloy andcarbon or an inorganic compound capable of reversibly inserting andextracting lithium. The negative electrode may also include a currentcollector, for example made of copper.

The liquid electrolyte generally comprises at least one lithium saltsuch as, for example, the salts chosen from the group formed byLiCF₃SO₃, LiClO₄, LiN(C₂F₅SO₂)₂, LiN(CF₃SO₂)₂, LiAsF₆, LiPF₆, and LiBF₄.

The plasticizer optionally present is generally chosen from the groupformed by PEO oligomers, dibutyl phthalate (DBP) and propylene carbonate(PC).

The invention also relates to a process for manufacturing a lithiumelectrochemical cell battery comprising at least one positive electrode(or cathode), at least one liquid electrolyte comprising at least onelithium salt, and at least one negative electrode (or anode) comprisingan assembly of at least one layer of gelled separator GS, comprising atleast one polymer GP, able to be gelled by the liquid electrolyte, onthe negative electrode, of at least one layer of plasticized separatorPS, comprising at least one polymer PP, able to be plasticized by theliquid electrolyte, on said separator GS layer, and optionally of atleast one other layer of gelled separator GS, called GS_(a), comprisingat least one polymer GP, on said separator PS layer, the combination ofthese two or three layers constituting a separator between the negativeelectrode and the positive electrode, an assembly of said separator onthe positive electrode, and an impregnation of said separator by theliquid electrolyte.

In one method of implementing the process according to the invention,the positive electrode is generally manufactured in solution frompolymer PP, carbon, active material, plasticizer and solvent.

In another method of implementing the process according to theinvention, the positive electrode is generally manufactured by extrusionfrom polymer PP, carbon, active material and plasticizer.

In another method of implementing the process according to theinvention, the separator PS layer is generally manufactured in solutionfrom polymer PP, plasticizer and solvent.

In another method of implementing the process according to theinvention, the separator PS layer is generally manufactured by extrusionfrom polymer PP, plasticizer or liquid electrolyte.

In another method of implementing the process according to theinvention, the separator GS layer is generally manufactured in solutionfrom polymer GP, solvent and optionally plasticizer.

In another method of implementing the process according to theinvention, the separator GS layer is generally manufactured by extrusionfrom polymer GP, solvent and optionally plasticizer or liquidelectrolyte.

Preferably, the polymer PP is generally filled with at least one mineralcompound chosen, for example, from the group formed by MgO, SiO₂, Al₂O₃,TiO₂, BaTiO₃ and lithium salts such as LiAlO₂ and LiI.

Preferably, the polymer GP is generally filled with at least one mineralcompound chosen, for example, from the group formed by MgO, SiO₂, Al₂O₃,TiO₂, BaTiO₃ and lithium salts such as LiAlO₂ and LiI.

In one method of implementation, the two or three PS and GS layers arejoined together into a separator by hot lamination or hot calendering.The term “lamination” is understood to mean passing the layers betweentwo rolls, the gap between which is kept constant. The term“calendering” is understood to mean passing the layers between tworolls, the pressure applied by the two rolls being constant. Theexpression “hot lamination or hot calendering” is understood to mean anoperation carried out at a temperature generally between 50 and 140° C.for example about 130° C. The pressure exerted by the rolls is generallybetween about 5 psi and about 30 psi, that is to say between about 0.035MPa and about 0.21 MPa, for example about 20 psi (i.e. about 0.14 MPa).

In another method of preparation, said layers form a three-layerseparator obtained by passing the separator PS layer into a solution ofpolymer GP, or into a solution of liquid electrolyte in which thepolymer GP has been dissolved.

In another method of preparation, said layers form a bilayer separatorobtained by passing a separator PS layer, preassembled with the positiveelectrode, into a solution of polymer GP or into a solution of liquidelectrolyte in which the polymer GP has been dissolved.

The positive electrode and the separator are generally joined togetherby hot lamination or hot calendering in order to form a plastic complex.

In addition, the plasticizer(s) optionally present in the positiveelectrode separator assembly is (are) removed by washing or vacuumextraction so as to obtain an assembly containing virtually noplasticizer.

The separator/positive electrode assembly, preferably containingvirtually no plasticizer, is generally brought into contact with thenegative electrode by a lamination or calendering step optionallycarried out hot.

The polymer PP, the polymer GP, the positive electrode, the negativeelectrode, the liquid electrolyte and the plasticizer are, within thecontext of the process according to the invention, generally chosen inthe same way as explained above in the case of the battery according tothe invention.

Finally, the invention relates to the use of a battery as describedabove or manufactured according to the process as described above for ahybrid vehicle, an electric vehicle, for a stationary application (i.e.emergency power supply provided by a battery in the case of a breakdownof the electrical mains) or portable equipment application.

The invention will be more clearly understood and other features andadvantages will become apparent on reading the following description,which is given by way of nonlimiting example and with reference to FIGS.1 to 7.

FIG. 1 shows a schematic cross section through a battery having abilayer separator according to the invention.

FIG. 2 shows a schematic cross section through a comparative batteryaccording to the prior art.

FIG. 3 shows the percentage recovered capacity (C in %) as a function ofthe number of cycles (N) for the battery according to the invention ofFIG. 1 and for the battery according to the prior art of FIG. 2, underslow cycling.

FIG. 4 shows the percentage recovered capacity (C in %) as a function ofthe number of cycles (N) for the battery according to the invention ofFIG. 1, under rapid cycling.

FIG. 5 shows a schematic cross section through a battery according tothe invention.

FIG. 6 shows the percentage recovered capacity (C in %) as a function ofthe number of cycles (N) for a battery according to the invention ofFIG. 5.

FIG. 7 shows a schematic cross section through a battery having athree-layer separator according to the invention.

FIG. 1 shows a schematic cross section through a battery 10 having abilayer separator (3, 4) according to the invention. The battery 10comprises the negative electrode collector 1, for example made ofcopper, a negative electrode 2 (the active part) which is, for example,a layer of Li metal, a layer 3 consisting for example of a PEO layer, alayer 4 consisting for example of a layer of PVDF-HFP containing 12 mol% HFP, a layer 5 (the active part of the positive electrode) and apositive electrode current collector 6, for example made of aluminum.The presence of the collector 1 is not essential—this is why collector 1has been shown in dotted lines.

FIG. 2 shows a schematic section through a comparative battery 11according to the prior art, which comprises all the elements of FIG. 1in the case when a connector 1 is present, except for the layer 3.

FIG. 3 will be commented upon below in Example 1.

FIG. 4 will be commented upon below in Example 2.

FIG. 5 is a schematic cross section through a battery 12 having abilayer separator (13, 14) according to the invention, which comprisesall the elements of FIG. 1 with the exception of the layer 3. Instead ofthe layer 3 there is a layer 13 that consists, for example, of a PEO gellayer, spread for example with a brush over the layer 4 duringmanufacture of the battery 12.

FIG. 6 will be commented upon below in Example 4.

FIG. 7 shows a schematic cross section through a battery 14 having athree-layer separator (3, 4, 15) according to the invention, the battery14 comprises all the elements of FIG. 1, to which has been added a later15, for example made of PEO, between the layer 4 and the layer 5.

EXAMPLES

The examples below illustrate the invention without in any way limitingits scope.

Process for Manufacturing the Battery According to the Invention ofExamples 1 and 2

The manufacturing process described below relates to the manufacture ofa single-cell battery 10, that is to say a battery consisting of asingle succession of a negative electrode (5, 6), a positive electrode(1, 2) and a bilayer separator (3, 4) consisting of a layer 3 of polymerGP, which is for example PEO gelled by liquid electrolyte, and of alayer 4 of plasticized polymer, which is for example PVDF-HFP, the layer3 being placed between the negative electrode (1, 2) and the layer 4,and the layer 4 being placed between the positive electrode (5, 6) andthe layer 3. In the case described in Examples 1 to 4, the negativeelectrode (1, 2) comprises lithium metal 2, optionally with a coppercollector 1. The positive electrode (5, 6) comprises an aluminum currentcollector 6 and a layer 5 of active material.

The PEO layer 3 is manufactured from a PEO/acetonitrile mixture, theacetonitrile being left to evaporate for several hours on a glass plateor on a sheet of Mylar®. Typically it has a thickness of 15 um. ThePVDF-HFP layer 4 is obtained using a technology that consists inspreading, onto a Mylar® support, using a device of the doctor-bladetype, a solution comprising PVDF-HFP, DBP (dibutyl phthalate), SiO₂ andacetone. A plastic layer for the positive electrode is obtained byspreading a solution comprising PVDF-HFP, DBP, active material (LiV₃O₈)and carbon in weight ratio of 10:1. Assembly of the cell comprisesfirstly thermal bonding of the plastic positive electrode 5 to thealuminum current collector 6 by hot calendering at a temperature closeto 135° C. and at a pressure of about 20 psi (i.e. about 0.14 MPa). Theresulting assembly is then bonded hot lamination, at a temperature closeto 130° C. and at a pressure of about 20 psi (i.e. about 0.14 MPa), tothe two layers 3 and 4 of the bilayer separator (3, 4) (PVDF-HFP, PEO).The DBP is then extracted by passing the assembly through an ether bathin order to obtain a porous membrane. This porous membrane is then driedand placed inside a glove box of the Jacomex type, for example a JacomexBS53INMT4 glove box, guaranteeing a moisture content of less 1 ppm,filled with an inert gas (argon) in order for the material once again tobe imbibed with a liquid electrolyte. This liquid electrolyte fills thepores left vacant by the plasticizer and gels the PEO. Finally, themembrane (3, 4, 5, 6) thus obtained is deposited on the Li metalnegative electrode 2 hot-laminated beforehand onto a copper grid 1 ascurrent collector. It is important to note that the Li/electrolyteinterface is formed in situ via the formation of a gel during thecontacting of the PEO layer with the liquid electrolyte. The assembly isthen hermetically sealed in an aluminum-lined plastic bag (of the “BlueBag” type from Shield Pack) for electrochemical testing.

It may be noted that the PVDF-HSP/PEO separator (3, 4) can also bemanufactured according to the invention in another way, namely:

-   -   passing the PVDF-HFP membrane through a PEO acetonitrile        solution so as to leave a thin film on the surface or covering        the membrane, for example using a brush, with said thin film        (see Example 3);    -   passing the PVDF-HFP membrane through a liquid electrolyte in        which a certain quantity of PEO has already been dissolved (see        Example 4).

Example 1 Slow Cycling of a Battery

A battery comprising an LiV₃O₈-based positive electrode (5, 6), aPVDF-HFP/PEO separator (3, 4), consisting of two layers 3 and 4, and alithium metal negative electrode (1, 2), mounted under the conditionsdescribed above, was galvanostatically cycled between 3.5 and 2 volts ata rate equivalent to the insertion of one lithium ion in 5 hours. Theliquid electrolyte used was a mixture of ethylene carbonate andpropylene carbonate, in a 1:1 mass ratio, and of a lithium salt known asLiTFSI (lithium trifluoromethanesulfonimide) (in fact the saltLiN(CF₃SO₂)₂ sold under the brand name FLUORAD™ HQ-115 by 3M) in aconcentration of 1 mol per liter of solvent. FIG. 3 shows the percentagerecovered capacity (C in %) as a function of the number of cycles (N),indicated by curves 7 and 8. Curve 7 is the curve obtained with abattery 10 according to the invention, as shown schematically in FIG. 1.Curve 8 is the curve obtained with a comparative battery 11, as shownschematically in FIG. 2. Comparison between the two curves 7 and 8 showsthat the insertion of a gelled PEO layer between the lithium metal anodeand the PVDF/HFP-based separator, allows a battery to undergo more than120 cycles, while maintaining a capacity of more than 80% of its.initial capacity (the end-of-life criterion for industrial batteries).

Example 2 Rapid Cycling of a Battery According to Example 1

To approach the industrial requirements in terms of cycling rate, thebattery 10 shown in FIG. 1 underwent the following electrochemical testprogram:

-   -   a first cycle comprising a discharge at −0.2 mAh/cm² and a        charge at 0.1 mAh/cm²    -   the other cycles comprise a discharge of the battery in 2 hours        (C/2) and a charge in 10 hours (C/10).

In both cases, the limiting voltages were 3.3 V and 2 V.

FIG. 4 shows the percentage recovered capacity (C in %) as a function ofthe number of cycles (N). Curve 9 is the curve obtained with a batteryaccording to the invention as shown schematically in FIG. 1. Duringthese tests, the technique of operating the battery 10 was the same asin the preceding example.

Despite a high discharge rate, it was found that the battery accordingto the invention using a PEO layer (the PEO being completely gelledafter contacting with the liquid electrolyte) between the lithium andthe PVDF/HFP-based separator is capable of recovering more than 80% ofits initial capacity after 350 cycles.

Example 3 Battery Constructed from a PVDF Membrane Coated with a PEOSolution

In the previous two examples, the PEO was prepared in the form of alayer before being brought into contact with the liquid electrolyte. Inthe present example, so as advantageously to eliminate one step in themanufacturing process, the PEO was used directly in gel form. To dothis, a solvent (typically acetonitrile) was added to the PEO in orderto obtain a gel. Such a battery is shown schematically in FIG. 5. A thinlayer of this solution was spread, using a brush, over the surface ofthe lithium. Parallel, the cathode/PVDF-HFP separator assembly wasimpregnated with liquid electrolyte. All this was assembled to form abattery. Thus, the PEO was used directly in gel form.

Example 4 Battery Constructed from a PVDF Membrane Impregnated with aLiquid Electrolyte in Which PEO has Been Dissolved

The same principle, explained in Example 3, may be transposed using theliquid electrolyte EC/PC/LiTFSI (1 mol/l) as solvent for the PEO. Inthis case, the cathode/PVDF-HFP separator complex was imbibed with thegel. The battery cycling conditions shown were the same as in Example 2.The battery tested is shown schematically in FIG. 5.

The capacity retention is identical to that obtained in batteries usinga PEO layer.

FIG. 6 shows the percentage recovered capacity (C in %) with respect tothe number N of cycles for a battery 12 as shown in FIG. 5. Curve 18 isthe curve obtained with such a battery 12 according to the invention.

It may be seen that the capacity retention is identical to that obtainedin the batteries according to the invention using a PEO layer.

1-25. (canceled)
 26. A lithium electrochemical cell battery comprisingat least one positive electrode, at least one liquid electrolytecomprising at least one lithium salt, and at least one negativeelectrode, wherein said battery comprises at least one layer of a gelledseparator GS comprising at least one polymer GP, able to be gelled bythe liquid electrolyte, which is at least partly gelled by the liquidelectrolyte, in contact with the negative electrode, and in that itincludes at least one layer of a plasticized separator PS comprising atleast one polymer PP, able to be plasticized by the liquid electrolyte,which is in contact with the layer of separator GS.
 27. The batteryaccording to claim 26, wherein the separator PS layer is at least partlyin contact with the positive electrode.
 28. The battery according toclaim 26, wherein the battery comprises, in addition, another separatorGS layer, at least partly between the positive electrode and theseparator PS layer.
 29. The battery according to claim 26, wherein thepolymer PP is selected from the group consisting of polyvinylidenefluoride PVDF, polystyrene PS, polyvinyl chloride PVC, polycarbonate PC,ethylene-propylene-diene monomer EPDM, and derivatives thereof;preferably, the polymer PP is selected from the group consisting ofpolyvinylidene fluorides PVDFs and (polyvinylidenefluoride)-co-(hexafluoropropylene) PVDF-HFP copolymers, and even morepreferably the polymer PP is a PVDF-HFP.
 30. The battery according toclaim 26, wherein the polymer GP is selected from the group consistingof polymethyl methacrylate PMMA, polyethylene oxide PEO andpolyacrylonitrile PAN, and derivatives thereof, preferably, the polymerPG is PEO.
 31. The battery according to claim 26, wherein the positiveelectrode comprises carbon, active material, polymer PP and optionallyat least one plasticizer.
 32. A process for manufacturing a lithiumelectrochemical cell battery comprising at least one positive electrode,at least one liquid electrolyte comprising at least one lithium salt,and at least one negative electrode comprising an assembly of at leastone layer of gelled separator GS, comprising at least one polymer GP,able to be gelled by the liquid electrolyte, on the negative electrode,of at least one layer of plasticized separator PS, comprising at leastone polymer PP, able to be plasticized by the liquid electrolyte, onsaid separator GS layer, and optionally of at least one other layer ofgelled separator GS, comprising at least one polymer GP, on saidseparator PS layer, the combination of these two or three layersconstituting a separator between the negative electrode and the positiveelectrode, an assembly of said separator on the positive electrode, andan impregnation of said separator by the liquid electrolyte.
 33. Theprocess according to claim 32, wherein the positive electrode ismanufactured in solution from polymer PP, carbon, active material,plasticizer and solvent.
 34. The process according to claim 32, whereinthe positive electrode is manufactured by extrusion from polymer PP,carbon, active material and plasticizer.
 35. The process according toclaim 32, wherein the separator PS layer is manufactured in solutionfrom polymer PP, plasticizer and solvent.
 36. The process according toclaim 32, wherein the separator PS layer is manufactured by extrusionfrom polymer PP, plasticizer or liquid electrolyte.
 37. The processaccording to claim 32, wherein the separator GS layer is manufactured insolution from polymer GP, solvent and optionally plasticizer.
 38. Theprocess according according to claim 32, wherein the separator GS layeris manufactured by extrusion from polymer GP, and optionally plasticizeror liquid electrolyte.
 39. The process according to claim 32, whereinthe polymer PP is generally filled with at least one mineral compoundselected from the group consisting of MgO, SiO2, Al2O3, TiO2, BaTiO3,LiI and LiAIO2.
 40. The process according to claim 32, wherein thepolymer GP is generally filled with at least one mineral compoundselected from the group consisting of MgO, SiO2, Al2O3, TiO2, BaTiO3,LiI and LiAIO2.
 41. The process according to claim 32, wherein the twoor three PS and GS layers are joined together into a separator by hotlamination or hot calendering.
 42. The process according to claim 32,wherein said layers form a three-layer separator obtained by passing theseparator PS layer into a solution of polymer GP, or into a solution ofliquid electrolyte in which the polymer GP has been dissolved.
 43. Theprocess according to claim 32, wherein said layers form a bilayerseparator obtained by passing a separator PS layer (4), preassembledwith the positive electrode, into a solution of polymer GP or into asolution of liquid electrolyte in which the polymer GP has beendissolved.
 44. The process according to claim 32, wherein the positiveelectrode and the separator are generally joined together by hotlamination or hot calendering in order to form a plastic complex. 45.The process according to claim 32, wherein the plasticizer(s) optionallypresent in the positive electrode/separator assembly is (are) removed bywashing or vacuum extraction so as to obtain an assembly containingvirtually no plasticizer.
 46. The process according to claim 32, whereinthe separator/positive electrode assembly, preferably containingvirtually no plasticizer, is generally brought into contact with thenegative electrode by a lamination or calendering step.
 47. The processaccording to claim 32, wherein the plasticizer optionally present isselected from the group consisting of PEO oligomers, dibutyl phthalate(DBP) and propylene carbonate (PC).
 48. The process according to claim32, wherein the polymer PP is selected from the group consisting ofpolyvinylidene fluoride PVDF and (polyvinylidenefluoride)-co-(hexafluoropropylene) PVDF-HFP; preferably, the polymer PPis PVDF-HFP.
 49. The process according to claim 32, wherein the polymerGP is selected from the group consisting of polyethylene oxide PEO andpolyacrylonitile PAN, and derivatives thereof, preferably, the polymerGP is PEO.
 50. A hybrid vehicle, an electric vehicle, or a stationary orportable equipment including a battery of claim
 26. 51. A hybridvehicle, an electric vehicle, or a stationary or portable equipmentincluding a battery manufactured by the process of claim 32.